A visit at this year’s Hannover fair has shown once again: Human-robot collaboration is booming. Both new as well as established robotics manufacturers are launching so-called cobots. More and more gripper solutions for HRC applications are becoming available, as are innovative software products facilitating easy cobot programming. However, to date HRC still seems to be limited to robots lifting a maximum of 15 kilograms – weights that could easily be manipulated by humans rather than cobots. So where’s the real benefit for industrial applications? And what is the actual advantage of human-robot collaboration?
KEBA has been extensively dealing with these issues over the last months. Schrattbauer draws the following first conclusions: “The developments we’ve seen in cobotics are important and necessary in a long-term perspective. However, in the short and medium term a different kind of HRC is much more valuable for users and operators – Heavy Load Robot Collaboration.” Generally speaking, HRC tries to effectively combine humans and robots to ensure that they interact smoothly, with both sides sharing their strengths. Schrattbauer: “Humans are still the best sensors available on the market. They have superior problem-solving skills. Industry robots, on the other hand, are perfect manipulators for heavy loads that work with utmost precision. Combining the two in a clever way results in ergonomic and safe workplaces as well as cost-efficient and flexible automation solutions. This win-win situation boosts process stability and product quality.” According to Schrattbauer, our primary goal for human-robot interaction must be to significantly simplify robot operations, moving from an expert to a user paradigm. Against this background, KEBA has developed a new operating device: KeTop G10 works with a 6D mouse completed with push button and LEDs for intuitive robot guidance. It is equipped with an enabling switch that ensures safe movements. In just a few steps, KeTop G10 can be mounted in different positions to a tool, workpiece or robot. This ensures that the operating device is always in the perfect place for every task.
Thanks to a force sensor communicating between the robot and the tool as well as a specially developed weight compensation system, the operator can step in and directly move the robot by adjusting the tool or workpiece. This allows every production worker to precisely and effortlessly move heavy loads. Humans could even use smart devices to enter into a dialog with the robot. The robot sends important information to the operator’s display, allowing the operator to interact with the robot hands-free.
“One major challenge we tackled was switching between self-controlled robot movements and operator-controlled movements,” Schrattbauer explains. This transition is critical to fully benefit from both strengths. Robots need to autonomously perform known and consistent movements. At the same time, a seamless transition to a manual steering mode must be possible. The classic control only allowed manual steering in the T1 operation mode. Switching to this mode would end the automatic mode. So there was no smooth transition between robot-controlled and operator-controlled movements. This problem was solved by expanding the automatic mode with commands and sequences that allow manual steering followed by automatic movements.
Another issue that is frequently ignored in smaller cobots is safe and task-oriented manual steering. For test applications, it may be sufficient to enable free movement and orientation of the robot in all directions. In practice, however, only few applications can be operated swiftly and efficiently with such a system. Here’s an example: If you enable a 7-axis robot to move all axes freely, it will be incapable of supporting manual steering. The robot might change the orientation of a tool although the operator really only wanted to move the robot in space. This means that in the manual steering mode, the operator constantly has to consider and check the position and orientation of the robot and the tool. The operator therefore is busy monitoring parameters that have already been set (such as orientation) rather than focusing on the actual task.
KEBA has therefore developed a “robot lane keeping assistant” for tasks where a workpiece or tool has to be moved along an absolutely straight line for only a few centimeters. Just like in a car, the assistant helps the operator stay on track, park safely and without collisions or even move autonomously over certain distances. In other words: The lane keeping assistant ensures that the robot remains within the predefined space and communicates deviations with a force feedback system. Simple assistants that, for example, allow the operator to enable or disable specific movement directions have been integrated in the system and significantly simplify robot guidance, letting the operator focus on the actual tasks.